Process for production of cellulosic materials with increased oxidizing capacity

ABSTRACT

A PROCESS FOR PRODUCING CELLULOSIC MATERIALS WITH OXIDIZING CAPACITY. CELLULOSIC MATERIAL TO WHICH A CARBAMATE-FORMALDEHYDE ADDUCT HAS BEEN APPLIED, IS TREATED WITH HYPOBROMITE SOLUTION. AFTER TREATMENT WITH HYPOBROMITE SOLUTION THE TEXTILE RETAINS POSITIVE BROMINE AND HAS HIGH OXIDIZING CAPACITY.

United States Patent Oflice U.S. Cl. 8-115.6 18 Claims ABSTRACT OF THE DISCLOSURE A process for producing cellulosic materials with oxidizing capacity. Cellulosic material to which a carbamate-formaldehyde adduct has been applied, is treated with hypobromite solution. After treatment with hypobromite solution the textile retains positive bromine and has high oxidizing capacity.

A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

It is known that the treatment of cellulosic textiles, to which a carbamate-formaldehyde adduct has been applied, with inorganic hypochlorites results in the formation of chloroamides on the textile. The chlorine in these moieties is positive chlorine, and has oxidizing capacity. Cellulosic textiles treated with carbamate-formaldehyde adducts, however, retain relatively low levels of positive chlorine and have little oxidizing capacity. For this reason, there is little use of the textile for its oxidizing capacity.

In the instant invention, unmodified or modified cellulosic textiles are treated with carbamate-formaldehyde adducts commonly used in finishing cellulosic textiles for special properties, such as Wrinkle resistance, or with modified adducts of the same type. Typical examples are N-methylol alkyl carbamates, N-methylol hydroxyalkyl carbamates and N-rnethylol alkoxyalkyl carbamates. Higher oxidizing capacities are imparted to the finished textile materials by treatment with hypobromite solutions than by treatments with hypochlorite solutions. Cellulosic products that have been chemically modified before treatment with the carbamate-formaldehyde adduct may be used in the process. Such modifications may be used, as described in US. Pat. 3,304,147, to further increase oxidizing capacity or to protect the cellulosic product from degradation by the bound bromine under adverse storage.

Although many methylol amide adducts are capable of reaction with cellulose and of retaining chlorine in the positive form, most are not suitable for use in this invention. Substitution of hypobromite for hypochlorite will result in products with lower oxidizing power in most instances. Methylol carbamates, however, are quite suitable, and bromination of cellulose treated with the carbamateformaldehyde adducts, provides products with high oxi- 3,592,582 Patented July 13, 1971 dizing capacities. The products of this invention are useful for oxidation of materials in solution whereby the residue of reduced oxidizing agent, in the form of a textile product or loose insoluble material, can be removed readily to minimize contamination of the solution. They are also useful for the making of protective clothing whereby a wearer can be protected from injurious materials that can be rendered innocuous by oxidation.

The amide-formaldehyde adducts useful in this invention are carbamate-formaldehyde adducts. Typical examples are the N-methylol' derivatives of methyl carbamate, ethyl carbamate, isopropyl carbamate, hydroxyalkyl carbamates and alkoxyalklyl carbamates. These may be applied to unmodified or modified cellulosic materials by treatment with an aqueous solution of the carbamateformaldehyde adduct followed by drying and heat treatment. Acidic or alkaline catalysts are used in this treat ment ordinarily, but may be omitted in many cases with modified cellulosic materials containing acidic groups such as phosphonomethyl and carboxyl groups.

An application depositing 0.1% to 1% nitrogen in the cellulosic material is satisfactory for the purpose of this invention. Introduction of positive bromine is accomplished most economically by treatment with aqueous solutions of 0.1 to 1.0% of an alkali metal hypobromite, such as sodium hypobromite. It may be accomplished, however, by use of organic hypobromites or bromamines.

The invention is illustrated by the following examples to which it is not limited.

EXAMPLE 1 Dimethylol carbamates were prepared by reaction of formaldehyde with the carbamate in a molar ratio of 2.2 to 1 at pH 10 for 45 minutes at 56 C. The monomethylol carbamate was prepared under similar reaction conditions with a 1 to 1 molar ratio of formaldehyde to carbamate.

Cotton printcloth was padded to about wet pickup with a solution containing 10% of dimethylol methoxyethyl carbamate and 4% magnesium chloride hexahydrate catalyst, dried, cured one minute at 180 C., afterwashed and dried.

Cotton printcloth was padded to about 80% wet pickup with a solution containing 10% of one of the following carbamate-formaldehyde adducts: monomethylol methyl carbamate, dimethylol methyl carbamate, dimethylol ethyl carbamate, dimethylol isopropyl carbamate, or dimethylol hydroxyethyl carbamate, and 0.06% zinc nitrate hexahydrate catalyst, dried, cured 3 minutes at C., afterwashed and dried.

A portion of each treated fabric was chlorinated with a solution of sodium hypochlorite containing 0.25% available chlorine at pH 9.5, thoroughly rinsed and air dried. Another portion of each treated fabric similarly was brominated with a solution containing an equivalent concentration of sodium hypobromite.

The measure of oxidizing capacity of each chlorinated and brominated sample was determined by titration of the iodine released from acidified potassium iodide solution. The results are illustrated in the following table:

Nitrogen content, 01, Ox. cap., Br, Ox. cap., Carbamate treatment percent percent meq./kg. percent meq./kg.

Monomethylol: methyl 0. 53 0. 42 118 2. 70 338 Dimethylol:

Methyl 0. 71 0. 14 30 1. 40 Ethyl 0. 63 0. 06 17 1. 16 145 Isopropyl 0. 62 0. 04 11 1. 14 143 Hydroxyethyl. 0. 67 0. 10 28 0. 72 90 Methoxyethyl 0. 50 0. 16 0. 94 118 In every instance, the fabrics exhibited greater oxidizing capacity after treatment with hypobromite solution than after treatment with hypochlorite solution.

EXAMPLE 2 Cotton printcloth was carboxymethylated by the process of U.S. Pat. 2,448,153 to a D8 of 0.06 (an average of 0.06 carboxymethyl groups for each anhydroglucose unit of the cellulose). The material was soaked in (wt/wt.) solution of hydrochloric acid to convert the sodium salt of the carboxyl group to the acid form, rinsed and dried.

Swatches of this fabric were tretaed with monomethylol methyl carbamate which had been prepared by the reaction of one mole of formaldehyde with one mole of methyl carbamate at pH 10. The fabric was padded to about 100% wet pickup of a solution containing N-methylol methyl carbamate and 0.6% zinc nitrate hexahydrate as catalyst, mounted on pin frames, dried at 60 C. for seven minutes, cured at 160 C, for three minutes, afterwashed with an alkaline solution of a nonionic detergent and dried. Breaking strength was then determined (American Society for Testing Materials, test method D83 9-59 A portion of the treated sample was chlorinated as in Example 1 and another portion was brominated as in Example 1. A portion of each halogenated fabric was titrated as in Example 1 to determine oxidizing capacity. A portion of each halogenated fabric'was tested for susceptibility to halogen damage by scorching and determination of breaking strength according to Tentative Test Method 92-195 8T of the American Association of Textile Chemists and Colorists. Results are shown in following table:

Modification--carboxymethyl:

After chlorination:

Available Cl, percent 0.26

Ox. cap., meg/kg. 73 Stretch retention in Scorch Test, percent 100 After bromination:

Available Br, percent 0.86 Ox. cap., mg./kg. 108 Stretch retention in Scorch Test, percent 74 tile,

(b) curing the impregnated material,

(c) treating the resulting cellulosic textile with a brominating agent, selected from the group consisting of an alkali metal hypobromite, an organic hypobromite, and a bromamine, which introduces positive bromine into the carbamate-formaldehyde condensate.

2. The process of claim 1 wherein the carbamate-formaldehyde adduct is a N-methylol alkyl carbamate.

give 0.5-0.7% nitrogen content on the cellulosic tex- 3. The process of claim 1 wherein the carbate-formaldehyde adduct is a N-methylol hydroxyalkyl carbamate.

4. The process of claim 1 wherein the carbamate-formaldehyde adduct is a N-methylol alkoxyalkyl carbamate.

5. The process of claim 2 wherein the carbamate-formalehyde adduct is monomethylol methyl carbamate.

6. The process of claim 2 wherein the carbamateformaldehyde adduct is dimethylol methyl carbamate.

7. The process of claim 2 wherein the carbamate-formaldehyde adduct is dimethylol ethyl carbamate.

8. The process of claim 2 wherein the carbamate-formaldehyde adduct is dimethylol isopropyl carbamate.

9. The process of claim 3 wherein the carbamate-formaldehyde adduct is dimethylol hydroxyethyl carbamate.

10. The process of claim 4 wherein the carbamateformaldehyde adduct is dimethylol methoxyethyl carbamate.

11. The process of claim 1 wherein the brominating agent is an alkali metal hypobromite.

12. The process of claim 11 wherein the alkali metal hypobromite is sodium hypobromite.

13. A process for preparing a chemically modified cellulosic textile with a radical containing a carboxylic which process comprises:

(a) etherifying the cellulose hydroxy groups of a cellulosic textile with a radial containing a carboxylic acid substituent to a degree of substitution of about 0.06 of said radical per anhydroglucose unit of the cellulose,

(b) treating the resulting etherified cellulosic textile with an carbamate formaldehyde adduct by impregnating the material with a suflicient quantity of the adduct to give about 0.6% nitrogen content on the etherified cellulosic textile,

(c) curing the impregnated material,

(d) converting the carboxylic acid substituent of the amide-formaldehyde treated fabric to the alkali metal salt form by washing with an alkaline solution,

(e) treating the resulting cellulosic textile with a brorninating agent selected from a group consisting of an alkali metal hypobromite, an organic hypobromite, and a bromamine which introduces positive bromine into the amideformaldehyde condensate.

14. The process of claim 13 wherein the etherifying radical is carboxymethyl.

15. The process of claim 13 wherein the amide-formaldehyde adduct is a methyl carbamate-formaldehyde condensate.

16. The process of claim 13 wherein the aimde-formaldehyde treatment of the etherified cellulosic material is carried out in the presence of an acidic catalyst.

17. The process of claim 13 wherein the brominating agent is an alkali metal hypobromite.

18. The process of claim 17 wherein the alkali metal hypobromite is sodium hypobromite.

References Cited UNITED STATES PATENTS 3,304,147 2/1967 Reinhardt 8-1163 3,300,273 1/1967 Kullman 81l6.3

DONALD LEVY, Primary Examiner B. BETI'IS, Assistant Examiner U.S. Cl. X.R. 8-1163 

